The present invention particularly relates to a slider structure for realizing an increased recording density of a magnetic disk drive.
A magnetic disk drive has a rotating magnetic disk and a magnetic head slider which has a read/write element mounted thereon and which is supported and positioned in a radial direction by a load beam. The slider runs relative to the disk to read and write magnetic information to and from the disk. The slider flies by an air wedge film effect serving as an air-lubricated bearing, and is kept from direct solid contact with the disk. In realizing a higher recording density and a resulting increased capacity or smaller size of the magnetic disk drive, it is effective to reduce a distance between the slider and the disk, i.e., a flying height of the slider.
In a design of the slider flying height, it is a conventional practice to provide a margin to allow for a possible reduction in the flying height caused by slider manufacturing variations and atmospheric pressure differences among environments where it is used. If this margin can be eliminated, the flying height of the read/write element can be reduced. To this end, a system has been proposed by, for instance, JP-62-250570A, in which a micro-actuator represented by a piezoelectric material is incorporated as a part of a slider to drive a read/write element and thereby individually and finely adjust the distance between the element and the disk. The system that controls the flying height of the read/write element by the micro-actuator as proposed in this official gazette is generally called an active head slider system.
A read/write element used in the existing products is separated into an inductive type write element and a read element utilizing a magnetoresistive (MR) effect, and they are formed by the photolithographic process at the trailing end of a slider, i.e., at the end face on the air discharge side. Near the read/write element are arranged positive/negative wires and pads for writing and for reading, i.e., a total of four wires and four wire pads.
The active head slider system proposed hitherto, though very effective in reducing the slider flying height, is inevitably more complex in slider structure than a rectangular parallelepiped slider of 1.25 mm length, 1 mm width and 0.3 mm height employed in the existing products. In addition to wires for the read/write element, wires for the micro-actuator are needed, making the wiring complex. Hence, it is difficult to secure the same space, 1 mm wide and 0.3 mm high, as in the existing magnetic disk drives at the air discharge end of the slider. The existing read/write element is therefore impossible or difficult to mount on the active head slider proposed hitherto.
Unlike the conventional active head slider system in which the read/write element is driven by the micro-actuator, the active head slider according to the invention is characterized by a slider structure in which a flying pad on an air bearing surface (ABS) is driven by the micro-actuator. Another feature of this invention is that the movable ABS pad is situated on the leading side of the trailing end face on which the read/write element is mounted.
In the slider structure of this invention, two wires for driving the micro-actuator need only to be installed in another area which is separate from four wires for the read/write element and in which a sufficient space is available. This arrangement allows the slider to be made active while mounting the existing read/write element and wires thereon.